Conventionally, a lamp according to the preamble is provided with at least one LED that is mounted on an LED semiconductor chip, which is mounted on the base. In this case, this base acts as a connecting component between the actual LED or the LED semiconductor chip and the reflector of the lamp. The mounting of the two components on each other can be done with a clip connection, for example. In this case, the base comprises elastic clips, for example, which are bent open when the reflector is inserted and lock into purpose-made slits, holes or passages on the reflector body.
The reflector itself comprises a longitudinal direction and an entry and exit opening, whereby the longitudinal direction of the reflector stretches from its entry opening to the exit opening. The exit opening is the opening through which the light emitted by the at least one LED leaves the reflector and hence the lamp. With most reflectors the longitudinal direction coincides with the optical axis and the axis of symmetry of the reflector and in this case, comprises the at least one LED.
The reflector very often comprises an inner surface that can be faceted, for example, in order to achieve the desired light emission characteristic. However, to do this it is necessary to arrange the LED in the desired position as precisely as possible. For example, with a reflector with an elliptical reflector inner surface, this can be a focus of the ellipse. It may also be beneficial to arrange the LED slightly in front of or behind this focus. The point where the LED must be arranged to achieve the desired light emission characteristic, in combination with the design of the reflector inner surface, is called the operating point. This is found mostly inside the reflector, so the LED protrudes through the entry opening of the reflector into the operating point. In order to achieve the desired emission characteristic, an exact a positioning as possible of the LED on the operating point is necessary.
The at least one reflector contact surface and the at least one base contact surface are provided to ensure this exact positioning. Both lie on top of each other when the reflector is connected to the base and thus prevent a further movement of the two components on top of each other. It is therefore possible to achieve a reproducible, very defined and well known positioning of the two components relative to each other. If the at least one reflector contact surface and the at least one base contact surface are produced accurately, the extent to which the LED protrudes into the reflector can be defined and reproduced in a precise way. Furthermore, should the LED not be arranged in the interior space of the reflector, the exact positioning of the reflector relative to the base is important. This situation also concerns the positioning of the reflector relative to the LED, so that the light emitted by the LED that enters the reflector through the entry opening possesses the desired emission characteristics when it leaves the reflector through the exit opening.
The reflector contact surface is conventionally the area directly around the entry opening of the reflector. In the connected state, this area of the reflector then preferably contacts the corresponding area of the base around the LED completely.
However, it is a disadvantage that this sort of lamp is relatively complex to produce. A reflector for a lamp of this sort is conventionally pressed from glass or glass ceramic. To do this, a mould is initially filled with a desired amount of glass or glass ceramic and then pressed in this mould between two movable moulding dies until it has the desired contour. The reflector that has been produced by this method is actually already fitted with an exit opening, but not yet with an entry opening. This is produced in a preferred embodiment of a method of this sort by a so-called “hot punch” method, whereby a mandrel or pin is guided through the pressed reflector at the desired point. So that the glass reflector does not shatter during this method, it must be heated or the insertion of the pin must occur at such a speed that the reflector has not yet cooled following the pressing. However, this leads to a deformation of the reflector area that is located around the desired entry opening. Yet as this area forms the reflector contact surface, it must have a complex finish, for example sawn or milled. This is complicated and therefore expensive. Furthermore, it is prone to errors, since the reflector contact surface that has been treated in this way must stand as exactly perpendicular as possible to the optical axis of the reflector, be as smooth as possible and be arranged precisely as possible at the correct height relative to the operation point of the reflector. As the serration or milling for the finishing of the reflector contact surface must take place in a separate step of the procedure, the relation to the optically relevant points on the inner surface of the reflector is compulsorily lost and thus the exact location of the operation point.
Moreover, a further tolerance of the saw cut or milling plane is added to the production tolerances that play a part during the pressing of the reflector and the production of the base. As a result, the precision achieved at a reasonable cost is greatly reduced.
Alternatively the entry opening could be created by, for example, milling in the reflector, rather than the “hot punch” method. This means that since the area surrounding the entry opening, which has been created in this way, is not or barely affected by the method, a complex post-treatment is unnecessary. However, the milling or drilling of the entry opening is time-consuming in comparison to the “hot punch” method and is therefore expensive. Furthermore, a separate tool must be used for milling, which adds to the above mentioned problems with production tolerance. Consequently this embodiment also has disadvantages.
Alternatively it is known from the prior art that, rather than producing the exact positioning of the reflector relative to the LED across the above described contact surfaces that are arranged around the entry opening, grooves or recesses can be made along the sides of the reflector neck, into which the structures on the base can lock into as precisely as possible. Serration or milling can also be used for this purpose. A backlash-free mounting could then also be achieved. However, the introduction of grooves or recesses into the pressed reflector creates a further step in the procedure and the resulting precision and tolerance problems. Moreover, a simple and exact positioning of the reflector relative to the LED is thereby not possible.
The WO 20121158404 A1 that was published after the filing date of the present application shows a reflector for a lamp whose reflector contact surface is arranged around the entry opening of the reflector. If the entry opening is made in the reflector body, the problems described occur as a result.
In EP 1 961 708 A1 a method is described to produce reflectors from glass, whereby the entry openings are created with the hot punch method in the reflector body. The part of the reflector body in which the entry openings are made is supported by a special holding device, so filament formation of the heated glass does not occur.
US 2004/0264200 A1 also deals with a method for producing a reflector for a lamp, in which various possibilities are given for creating the entry opening in the reflector body. However, in every method the lower area of the reflector body, in which the entry opening has been made, must be submitted to a thermal post treatment.
US 2011/0019409 A1, as well as DE 10 2010 031 312 A1, deals with the mounting of LED support elements on a lining. This should achieve as good a heat conductivity and thermal coupling as possible.
In WO 2011/104 255 A1 a so-called downlight, i.e. a lamp that shines downwards, is described, whereby the reflector is only held by placing it on a mounting ring. There is no contact with the base on which the LEDs are arranged.
In DE 10 2009 047 493 A1 a lamp device and a top unit for mounting on a lamp device are described, on which the locking element of a bayonet lock is arranged on the side of the reflector facing the LED. The reflector contact surface formed at the outer edge of the entry opening of the reflector.